Computed tomography distinction of central thoracic masses

Abstract

In an analysis of 36 central lung, 54 mediastinal, and 10 central pleural masses, features were sought that would allow accurate localization of the mass by CT. The mass-lung interface was the most useful feature; with few exceptions a mass with a spiculated, nodular, or irregular edge was in the lung, and a mass with a smooth edge was in the mediastinum. In the superior mediastinal, supraazygos, and supraaortic regions lung masses were lateral to the great vessels, and mediastinal masses were medial to the great vessels. Anterior mediastinal masses were typically positioned between the sternum and great vessels; some were more laterally positioned, however, and could only be distinguished from lung masses by the mass-lung interface. In the infraazygos, infraaortic, and paraspinal areas, lung and mediastinal masses were best differentiated by the mass-lung interface. The angles formed between the mass and lung were occasionally helpful in localizing the mass. Central pleural masses were characterized by a lack of intimate mediastinal effect, obtuse angles between the mass and lung, a smooth mass-lung interface, and characteristic association with other similar areas of involvement in the pleural space. These criteria were used for the correct localization of 99 of 100 masses; therefore, they can simplify and focus the work-up of most central thoracic masses.